NI PXI 2593 Bandwidth

[wcon56]

I use four NI PXI-2593 to test 60 channels signal,the signal is 40kHz~20MHz.

NI 2593 is 500MHz bandwidth,I think the 20MHz signal maybe OK.

But I connet the Agilent 33220A(50Ω) to COM0,and Tek 3034C ch1 to CH0,33220A give a 1MHz~20MHz/1Vpp sine ,but the signal(tek 3034C ch1) is 2Vpp~1.8Vpp,the signal(tek 3034C ch3) is 1.5Vpp~1.3Vpp.

 I want to know the 2593 real bandwith without loss. please give me some advices for use!